Artificial limb



March 9,1926. 1,57ss49 G. W. LEIRMANN ARTIFICIAL LIMB Filed July 11 1925 ven for.' George W Le'rmann. By M1 MLM /qzorneg Patented Mar. 9, 1926.

GEORGE W; LEIRMANN, OF MINNEAPOLIS, IMINNESOTA.

ARTIFICAL L11/1B.

Application mea July 11, 1925. semi No. 42,919.

i Limbs, of which the following is aspecitication.

My invention relates to artificial limbs. The invention is intended for the pedal eX- tremities and relates especially to an ankle joint construction. The invention is an improvement on that disclosed in my Patent No.

. 834,987, dated November 6, 1906. An object is to provide a durable ankle joint construction which when in use by the wearei" will operate in a manner of the natural ankle joint thereby making it possible to walk with ease on account ofthe freedom of movement provided for the foot member relatively to the leg member. In carrying out my invention I provide an angle bolt which permits the footinembcr to have a rocking movement longitudinally and sidewise and also for all intermediate positions. My construction entirely eliminates the use of elastic cords and springs in the ankle joint. The full objects and advantages of my invention will appear in' connection withthe detailed descrlption thereof and the novel features embodied in my inventive idea will be particularly pointed out in the claims.

In the accompanying drawings which illustrate a practical embodiment of my invention, Fig. 1 is a view of the artificial limb in central vertical section and partly broken away. Fig. 2 is a fragmentary'botto-m plan view. Fig. 3 is a view in section on the line 3-3 of Fig. 2. Fig. 4 is an elevational view of an ankle bolt. Fig. 5 is a perspective view of a pivot pin.

Referring to the construction shown in the drawings, the numeral 1() designates a foot member preferably constructed from wood in one piece and which may be shaped in accordance with the original foot of the wearer, so that in the case of amputation of one leg, a shoe may be worn which is like that worn on the natural foot. A leg member 12 is provided which has a socket 14'for receiving the stump of the amputated leg. The leg member 12 is preferably constructed of wood with a strip of wood 16 having the grain running in a different direction secured to the lower end thereof. Underneath the strip 16 is a block 18 of felt or other resilient material. Underneath the block 18 are two abutting blocks 20 and 22 of felt or similar material. The block 2O rests upon the heel portion of the foot member which is recessed to receive a boss 24 preferably cf resilient material, the upper end of which enters a recess in the block 20. The block 22 rests in a depression in the forward portion of thev foot member. A boss 26 preferably of resilient material fits into a recess formed at `the junction of the blocks 2G and 22 and the upper end of this boss is received in a recess in the block 18. The bosses prevent the foot member from twisting on the leg member. The material at the bottom of the socket in the leg member 12 is provided with a hole thru which an ankle bolt extends. This bolt consists Of two members 28 and 30 pivotally connected byV a pin 82 which passes thru a slot in the upper end of the bolt member 30, the bottom of the slot preferably having therein a piece of resilient material 34 to take up shocks. The pin 32 also passes thru holes inv the lower end of the bolt member 28, this end being formed as a` yoke having its branches straddling the upper end ofthe member 30. The upper end of the member 28 has a screw threaded portion which passes thru the hole in the lower portion of the leg member and receives a nut 36. The ankle bolt also passes thru holes in the blocks 18 and 20, these holes being larger than the bolt so that the latter may swing therein. The lower end of the bolt member 30 is formed,with an eye 38 thru which passes a pivot pin 40. The lower surface of the foot member is provided with a circular recess as will be understood from Fig. 2, which receives two opposite segmental metallic plates 42 and 44, held therein by screws 46 and these two plates are bent at right angles t-o provide downward projections 48 and 50. The foot member between these projections is cut entirely thru to provide a slot 52 thru which lthe lower end of the bolt member extends.

The pivot pin 40 passes thru holes in the projections 48 and 50. A pawl 54 is piv oted to the projection 50 by a rivet 56 which is headed down sufficiently to hold the pawl frictionally in whatever position it is turned. The pawl is adapted to engage a notch 58 formed in the curved surface of the pin 40 at the proper place between its ends.` lhen the pin has been passed thru the holes 'in the projection 48 and 50l the pawl is turnedv so as to it into the notch 58 as shown in Fig. 3 whereby the pin is securely held in place. In order that the pa-wl may be readily turned into the notch 58, one end of the pin is provided with a notch 60 for the reception of a screwdriver or similar implement. It is evident that the pivot pin 40 may be readily removed and replaced whenever it is desired to do so on account ot the construction just described. The ends of the sl-ot 52 are provided with pieces or felt 62 and 64 which serve as buffers for the bolt member SO. rlhe leg member 12 may be attached to the person in any customary or suitable manner.

The operation and advantages of my invention will be apparent in connection with the foregoinedescription. The pivot pin LO not only serves to secure the lower end of the ankle bolt to the 'foot member but permits the foot member to have a rocking movement in a longitudinal direction. rihe pin permits the toot member to have a rocking sidewise movement. These two pins together provide a universal joint so that the foot member can yielel or rock inany direction, the same as provided for by the natural ankle joint. The Afelt blocks normally leep the foot member in natural position and are sutiieiently yielding to permit a range et rocking movement about the same asthat a'torded by the human ankle joint. The extent of this rocking movement is readily regulated by turning the nut 36. The fact that the foot member is made in one piece without any toe joint is ot great advantage as, for instance, in going up and down stairs since it results in greater stability and increased leverage for the foot member as the wearer will not need to step beyond the toe joint as is the ease when such joint is used.

I claim:

l. An artificial limb comprising a leg member, a foot member having an opening therethru, resilient blocks placed between said members, a pair of spaced metallic members secured to said foot member adjacent said opening, a pivot pin secured to said metallic members, ajointed ankle bolt eX- tending into said opening and pivoted at its lower end on said pivot pin, a pivot pin eX- tending at right angles to said lirst pivot pin connecting the two members of' said bolt, and means for securing the upper bolt member to said leg member.

2. An artilicial limb comprising a leg member, a toot member having an opening therethru, resilient blocks placed between said members, a pair of spaced metallic mem bers having holes therein secured to said foot member adjacent said opening, a transverse pivot pin passing thru said holes, said pivot pin having a notch intermediate its ends, a pawl pivoted to one of said metallic members adapted to Vengage said. notch, a jointed ankle bolt extending into said opening and pivoted at its lower end on said pivot pin, a longitudinal pin connecting the two members of said bolt, and means for adjustably securing the upper bolt lnember tol said leg member'.

3. An artificial limb comprising a leg member, a toot member having a recess in its upper surface, upper and lower resilient blocks placed between said members, said lower block having a recess in its lower surface, a resilient boss engaging in said recesses, said lower blocl; having a recess in its upper surface and said upper block having a recess in its lower surface, a resilient boss engaging in said last mentioned recesses and a univer ally jointed ankle bolt connecting said leg and foot members.

In testimony whereof I hereunto affix my signature.

GEORGE lV. LEIRMANN. 

